Secreted phospholipase A2 and mast cells

Phospholipase A(2)s (PLA(2)s) are a group of enzymes that hydrolyze the sn-2 position of phospholipids to release (typically unsaturated) fatty acids and lysophospholipids, which serve as precursors for a variety of bioactive lipid mediators. Among the PLA(2) superfamily, secreted PLA(2) (sPLA(2)) enzymes comprise the largest subfamily that includes 11 isoforms with a conserved His-Asp catalytic dyad. Individual sPLA(2) enzymes exhibit unique tissue and cellular localizations and specific enzymatic properties, suggesting their distinct biological roles. Recent studies using transgenic and knockout mice for individual sPLA(2) isofoms have revealed their involvement in various pathophysiological events. Here, we overview the current state of knowledge about sPLA(2)s, specifically their roles in mast cells (MCs) in the context of allergology. In particular, we highlight group III sPLA(2) (PLA2G3) as an "anaphylactic sPLA(2)" that promotes MC maturation and thereby anaphylaxis through a previously unrecognized lipid-orchestrated circuit. Copyright (C) 2014, Japanese Society of Allergology. Production and hosting by Elsevier B.V. All rights reserved.